Road trips have been popular with Americans for almost as long as their love of cars. But when gasoline prices are high, people abandon the highway.

This summer, gasoline prices have fallen. And, more Americans are taking road trips once again.

The American Automobile Association says more than half of Americans are driving on highways this vacation season. Wherever they might travel, there is much to see along the way. The U.S. is well known for its so-called roadside attractions.

Roadside attractions are generally found near highways. They are usually free and are often huge representations of ordinary things. They are also often a bit weird.

No one exactly knows how many roadside attractions there are in the United States. Not everyone agrees on what makes something a roadside attraction.

June Julien is with the Steuben County Indiana Visitor’s Bureau. She says the website Roadside America lists about 15,000 such attractions.

“Well, some of the reasons to go to roadside attractions would be you’ve been in the car for hours, the children are antsy, the pets need some attention, and you can get out, you can stretch your legs, you can have a little bonding time with your family on something and you’re looking at something that’s different, you don't see it every day.”

Each state has hundreds of roadside attractions. Some are as simple as the meeting of three states in the middle of a lonely dirt road. A small sign marks the place where you can stand in Michigan, Indiana, and Ohio at the same time.

Others are huge, and can be seen for kilometers. The Smiley Face water tower in Indiana is one of more than 30 “smiling” water towers across the area.

Zack Dunaway is on a 12-hour road trip from Atlanta, Georgia, to Michigan. He is creating his own attractions along the way by taking selfies at every state line rest stop. “We’ve stopped several times to stretch your legs and rest your mind from the road.”

Mike Swartz is from Toledo, Ohio. He says stopping at roadside attractions is a great way to teach his children.

“Kids get to see a lot of different parts of the United States, put the screens down and get to talk to your mom and dad. Older kids probably don’t like that as much, but the younger kids -- it’s important for them to learn.”

Roadside attractions gained popularity after World War II, when soldiers returned home. The men had seen the world and were excited to explore their own country.

“As the highway system began to be developed, people started to travel. And this was before the advent of fast food restaurants. And there just weren’t a lot of places to pull off. And areas started to say ‘hey, we want these people off the roads, we want them in our areas spending money,’ and they started to maybe build things that would attract people.”

Restaurants and stores tried all sorts of tricks to appeal to travelers, including bright, big paintings on building walls and wild statues. Calling something the ‘world’s largest’ of its kind is a common title. These objects include the largest ball of twine, the largest rocking chair, and the largest tire.

Not all roadside attractions are manmade. Kokomo, Indiana, is home to the World’s Largest Bull. Old Ben died in 1910, and is now stuffed and under glass. He weighed 2140 kilograms and was almost 2 meters tall.

There are also strange sites, like trees with shoes hanging from their branches. A twisted house in the shape of an arrow brings in visitors too. In Huntington, Indiana, there is an outhouse collection open to the public.

As strange as these things are, Julien believes that roadside attractions do more than give travelers a break and bring money to the local communities.

“The more you travel, the wider your worldview is and the easier it will be for all of us in the long run to get along.”